Measurement of the Generalized Forward Spin Polarizabilities of the Neutron

The generalized forward spin polarizabilities 0 and LT of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since 0 is sensitive to nucleon resonances and LT is insensitive to the resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on LT show significant disagreement with chiral perturbation theory calculations, while the data for 0 at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.